Thomas J. Campbell is leaving as director of the Federal Trade Commission's Bureau of Competition, in charge of the FTC's antitrust activities, to join the law faculty at Stanford University. Though Campbell, 30, was brought into the FTC when Chairman James C. Miller III took over in the fall of 1981, rumors have persisted that the two disagreed over how strong the commission's trust-busting activities should be. Campbell's successor has not been announced, though word around the FTC is that the job will go to Timothy Muris, director of the Bureau of Consumer Protection and one of Miller's closest confidants.

Washington attorney David H. Martin will be nominated to run the Office of Government Ethics, an agency charged with preventing conflict of interest on the part of federal workers. Martin, a former counsel for the Secret Service, would succeed J. Jackson Walter, who resigned . . . . President Reagan also said he would nominate Harry O'Connor, a Californian who produced and syndicated Reagan's radio broadcasts from 1975 to 1979, to be a member of the board of the Corp. for Public Broadcasting.

William F. Pickard, owner and operator of six McDonald's restaurants in Detroit, will be nominated as a new member and, upon confirmation, chairman of the board of the African Development Foundation.